I Need Help!

I'd try and find out if an 83 318 is internally or externally balanced. If its internal, then a neutral (zero) balance flywheel should work, otherwise you need a specially balanced flywheel specific for your application.

Most of the 318's I've seen apart, had a pilot hole in the crank - but having said that, the ones intended for automatics are not usually machined large enough for the bronze pilot bushing. But never fear - in this case what you would want is a roller pilot bearing, these use the torque converter register in the crank instead of the smaller pilot hole - this is a part that mopar started using in their production cars and trucks sometime in the 90's (IIRC). Thats what I am using in my dart instead of the bushing.

Good hunting !